Hi I'm looking for a tool to hold the harmonic balancer in place while I torque it to spec I found this on Amazon but I'm not sure if it will fit a 2012 Prius https://a.co/d/6lhpBkU There is also this three pronged claw thing Ive seen a bunch come up in searches but I think it's just for pulling it off once the crank bolt has been removed.
You don't have any belts on this car so you just wrap a strap wrench around the pulley and hold the strap wrench in the direction you want to hold it I never heard of doing anything so crazy but that should work usually I just blast the bolt on and/or off seriously with the crankshaft pulley bolt I don't think you're going to really super over torque it unless you're just that kind of person I guess as that chuckle.
Take a large pry bar and put it through the pully against the block to hold it still. I don't remember what the torque is but it's not high. That's what I did.